Chris Huhne's wife revealed to the press that she had taken his speeding points in revenge for his affair with another woman, a court has heard.

Vicky Pryce was warned by a journalist that the revelation would inflict "maximum and perhaps fatal damage" on the senior Liberal Democrat.

But the economist and mother of three replied: "I have no doubt as I definitely want to nail him. More than ever actually and I would like to do it soon."

The declaration was contained in an email between Pryce, a former government adviser, and Isabel Oakeshott, a reporter for The Sunday Times.

Their exchanges before the story broke were revealed on the first day of Pryce's trial at Southwark Crown Court in London.

The case went ahead 24 hours after Huhne pleaded guilty to lying to police about the speeding offence, which was committed in 2003.

After repeated denials, the former energy secretary finally admitted his then wife had taken the points for him so he could avoid prosecution.

Huhne has now officially resigned as an MP after switching his plea to guilty and being warned he faces a likely prison sentence.

Pryce denies perverting the course of justice, claiming she was coerced into taking the points, and is now being tried alone.

Chris Huhne and girlfriend Carina Trimingham leaving court on Monday

Prosecutor Andrew Edis QC said the points swap came to light only in 2011 because the defendant had wanted to ruin her former husband's career.

The jury heard she was furious after Huhne abruptly ended their 26-year marriage and left her for PR consultant Carina Trimingham.

Pryce was told the bombshell news of the MP's affair - and that he had been rumbled by the press - as she watched a World Cup football match.

A year later, in March 2011, she tipped off the Sunday Times about their points swap and started considering the best way to destroy her ex via the press.

"Her revenge in the end was to pass the story of the 2003 points to the newspaper so they would publish it and destroy his political career," Mr Edis said. "It was Pryce's plan that she would get her revenge by putting an end to all that.

"She would publish what she and he had done together without complaint in 2003 so she would get her revenge for the undoubtedly very bad way he had treated her."

Ms Oakeshott recommended that the paper ran several pieces, including a front page story and news features.

"This is what I strongly recommend you do, given your dual objectives of bringing Chris down ... without seriously damaging your own reputation in the process," she said.

She later warned about the risk of criminal proceedings, after which Pryce wrote: "I would need some reassurance that it would bring Chris down."

Ms Oakeshott replied: "The bottom line is that this story will bring Chris down if you are prepared to go on the record, with the minor risk this carries.

"I think you can make yourself out to be very much the honourable one, saying it has very much been on your conscience ever since, saying you knew it was wrong but you were bullied into it."

Attempts by Pryce and the newspaper to elicit a confession from Huhne by recording phone calls were played to the court.

The jury heard the politician urging his ex-wife to "stop telling ridiculous stories" and "maliciously briefing the press" in a bid to blacken his name.

Pryce, at times angry and swearing as the MP continues to deny the crime, insisted she was not behind the newspaper speculation.

"Why would I tell anyone about me taking your points? It's not in my interests. Are you a moron?", she said.

Huhne repeatedly warned her not to talk to journalists and said the story would not come out if they do not "stand it up".

During the calls, Pryce also made several digs at Huhne's new partner Ms Trimingham, calling her "your f****** man".

In the four conversations, she told Huhne she did not want to "perjure" herself by denying the story, saying: "It's one of the things that always worried me when you made me take them in the first place."

Mr Edis said: "You might come to the conclusion that these telephone calls are two manipulative people trying unsuccessfully to manipulate each other."

The QC explained that the marital coercion defence could only apply if Pryce was made to feel that she had no choice but to take the points.

He said the jury would have to decide whether she was "weak-minded" and forced to help her husband, or a "strong-minded and manipulative" woman acting of her own free will.

"From the emails, she is certainly quite a subtle, clever person," he said.

He also pointed out that, in 2003, Pryce was a very senior civil servant and an economist with a good career in her own right who was free to support herself if her marriage ended.